Towards Monodisperse Star‐Shaped Ladder‐Type Conjugated Systems: Design, Synthesis, Stabilized Blue Electroluminescence, and Amplified Spontaneous Emission

Abstract

A novel series of monodisperse star-shaped ladder-type oligo(p-phenylene)s, named as TrL-n (n=1-3), have been explored. Their thermal and electrochemical properties, fluorescence transients, photoluminescence quantum yields, density functional theory calculations, electroluminescence (EL) and amplified spontaneous emission (ASE) properties have been systematically investigated to unravel the molecular design on optoelectronic properties. The resulting materials showed excellent structural perfection, free of chemical defects, and exhibited great thermal stability (T : 404-418 °C and T : 147-184 °C) and amorphous glassy morphologies. Compared with their corresponding linear counterparts FL-m (m=1-3), TrL-n showed only little bathochromic shifts (5-12 nm) for the absorption maxima λ in both solution and films. The star-shaped ladder-type compounds exhibited enhanced optical stability and suppressed low-energy emission. Their EL spectra exhibited excellent stability with increasing the driving voltage from 6 to 12 V. Moreover, superior low ASE thresholds were recorded for TrL-n compared with FL-m. Rather low ASE threshold (29 nJ per pulse or 1.60 μJ cm ) was recorded for TrL-3, demonstrating their promising potential as excellent gain media. This study provides a novel design concept to develop monodisperse star-shaped ladder-type materials with excellent structural perfection, which are vital for shedding light on exploring robust organic emitters for optoelectronic applications.

Frequency‐Upconverted Stimulated Emission by Up to Six‐Photon Excitation from Highly Extended Spiro‐Fused Ladder‐Type Oligo(p‐phenylene)s

“…Thesynthetic routes to the ladder-type precursors are outlined in Scheme S1 (Supporting Information), using similar procedures as we previously reported. [21] Due to the facile functionalization of spirobi-Scheme 1. Representation of the chemical structures of spiro-fused ladder-type oligo(p-phenylene)s (SpL(1)Àx,SpL(2)Ày,a nd SpLÀz, x, y, z = 1-3).…”

Frequency‐Upconverted Stimulated Emission by Up to Six‐Photon Excitation from Highly Extended Spiro‐Fused Ladder‐Type Oligo(p‐phenylene)s

“…Thesynthetic routes to the ladder-type precursors are outlined in Scheme S1 (Supporting Information), using similar procedures as we previously reported. [21] Due to the facile functionalization of spirobi-fluorene unit, spiro-fused ladder-type oligo(p-phenylene)s were formulated by stepwise synthetic strategies.T he synthetic strategies and detailed procedures for SpL(1)Àx, SpL(2)Ày and SpLÀz (x, y, z = 1-3) are shown in Schemes S2-S4. By using the synthetic methods,including palladium catalyzed Suzuki-cross coupling,F riedel-Crafts acylation/ alkylation reaction, and organic acid catalyzed intramolecular ring-closure alkylation, the spiro-fused ladder-type backbones have been constructed efficiently,a ttached with alkyl side chains and electron-donating end-cappers.…”

TD-DFT Simulation and Experimental Studies of a Mirrorless Lasing of Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)]

“…Polymers 2021, 13, x FOR PEER REVIEW 8 of 14 lasing, since most of the features are laser features [40]. Many CPs and COs are capable of producing optically pumped ASE [41,42]. PFO-co-PPV-MEHB in toluene at a concentration of 2.5 mg/mL was transversely excited with a 355 nm Nd: YAG laser.…”